A communication control system that implements communications by transmitting voice signals or video signals from a transmitting terminal to a receiving terminal through a communication line has been provided. However, depending on communication conditions, there is a case where a part or the whole of the voice signal or the video signal is lost in the communication line between the transmitting terminal and the receiving terminal, and the voice signal or the video signal does not reach the receiving terminal.
As a system to give a notification about a communication failure between the transmitting terminal and the receiving terminal to a user, the communication system disclosed in Patent Literature 1, for example, is known. The communication system is composed of a base station including a reception monitoring unit that monitors radio wave reception, an abnormal condition monitoring unit that monitors the abnormality of the base station and a message transmitting and receiving unit that transmits the abnormality of radio waves or the abnormality of the base station as a message and relays a message from a portable terminal, and a terminal including a reception monitoring unit that monitors radio wave reception, an abnormal condition monitoring unit that monitors the abnormality of the terminal, a message transmitting and receiving unit that transmits the abnormality of radio waves or/and the abnormality of the terminal as a message and receives a message from the base station and an audio processing unit that converts a message into audio and outputs it. When a failure such as disconnection of a call occurs, this communication system transmits a message indicating that the cause of the failure is one of radio wave interference, the abnormality of the terminal and the abnormality of the base station to the terminal and thereby allows a user to recognize the reason for the failure.